Depressive Symptoms Among Amphetamine and ... - APA PsycNET

Psychology of Addictive Behaviors 2002, Vol. 16, No. 4, 333–337

Copyright 2002 by the Educational Publishing Foundation 0893-164X/02/$5.00 DOI: 10.1037//0893-164X.16.4.333

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Depressive Symptoms Among Amphetamine and Cocaine Users Before and After Substance Abuse Treatment Kara S. Riehman and Martin Y. Iguchi

M. Douglas Anglin

RAND

University of California, Los Angeles

This study examined whether higher rates of depressive symptoms among amphetamine compared with cocaine users result from amphetamine use itself, polydrug use, or experiencing a major lifetime depressive episode and whether depressive symptoms among amphetamine users are more likely to persist 12 months after treatment. The association between amphetamine use and depressive symptoms disappears when controlling for polydrug use and lifetime major depressive episode. Polydrug use and lifetime depressive episode are significantly related to depressive symptoms in the year preceding treatment. Amphetamine use at intake does not predict depressive symptoms among individuals who are abstinent at follow-up, and amphetamine users are no more likely than cocaine users to report depression at a 12-month follow-up.

underlying condition of depression that predated drug use. Alternatively, A/MA users may be at increased risk of polydrug use, which itself may increase the likelihood of depressive symptoms. Last, use may be a self-medicating response to depression (Abraham & Fava, 1999). Although we could not test the self-medication hypothesis in this study, we use data from a national treatment sample to compare cocaine and A/MA users to determine whether A/MA use is associated with elevated levels of depressive symptoms at intake and after cessation of use. We hypothesized that A/MA use would be associated with depressive symptoms at the bivariate level but that polydrug use and lifetime depressive episodes would partially explain this relationship.

Since 1990, amphetamine/methamphetamine (A/MA) use has risen dramatically, particularly in the western United States (National Institute on Drug Abuse [NIDA], 2000). Use now appears to be increasing among juveniles and in the Midwest and Southeast (NIDA, 2000), yet little is known about treatments for, and treatment outcomes among, A/MA users (Huber et al., 1997). A/MA users tend to be White and male, have high rates of polydrug use, and to initiate A/MA use between 19 and 24 years of age (Gleghorn, Marx, Vittinghoff, & Katz, 1998; Maglione, Chao, & Anglin, 2000). A/MA use is also associated with many psychiatric disorders, including amphetamine psychosis (Rounsaville et al., 1991), experiencing hallucinations, and depressive symptoms (Rawson et al., 2002). Depressive symptoms are higher among A/MA users than other stimulant users (e.g., cocaine), and high prevalence rates of depressive symptoms have been reported among A/MA users in treatment (Kalechstein et al., 2000; Rawson et al., 2000). A/MA abusers appear to experience a long period of depressive symptoms after cessation of use (Rawson et al., 2002). It is not clear, however, whether these symptoms are more prevalent after treatment among A/MA users than among users of other stimulants or whether these symptoms affect treatment outcomes. It may be, for example, that A/MA users have higher rates of depressive symptoms because they are more likely to have an

Method Sample Data for this analysis come from the NIDA-sponsored Drug Abuse Treatment Outcome Studies (DATOS), a nationwide, multisite longitudinal study of patients admitted to drug treatment programs in Chicago; Houston, Texas; Miami, Florida; Minneapolis, Minnesota; Newark, New Jersey; New Orleans, Louisiana; New York; Phoenix, Arizona; Pittsburgh, Pennsylvania; Portland, Oregon; and San Jose, California, from 1991 to 1993 (see Flynn, Craddock, Hubbard, Anderson, & Etheridge, 1997, for a description of DATOS). The DATOS intake sample included 10,010 individuals admitted to treatment during 1991–1993 who received face-to-face interviews on treatment entry. The follow-up sample was weighted to represent individuals who remained in treatment at least 3 months and only included clients from programs with at least 20 DATOS participants, to allow for analysis of program differences (Flynn, et al., 1997). Of the 4,786 clients targeted for follow-up interviews, 557 were determined to be ineligible, leaving 4,229 eligible clients. Of those, 2,966 (70%) were located and reinterviewed. This analysis includes male and female adults in treatment who completed both an intake and follow-up and who reported cocaine or A/MA use in the

Kara S. Riehman and Martin Y. Iguchi, Drug Policy Research Center, RAND, Santa Monica, California; M. Douglas Anglin, Integrated Substance Abuse Programs, University of California, Los Angeles (UCLA). This research is supported by funding from National Institute on Drug Abuse (NIDA) Institutional Training Grant DA07272 to the UCLA Drug Abuse Research Center, NIDA Grant U01-DA10378 (Drug Abuse Treatment Outcome Studies), and the RAND Drug Policy Research Center. Correspondence concerning this article should be addressed to Kara S. Riehman, RAND, 1700 Main Street, P.O. Box 2138, Santa Monica, California 90407-2138. E-mail: [email protected] 333

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past year (N ⫽ 2,216). Forty respondents were missing valid data on key items and were excluded from the analysis, yielding a final sample size of 2,176. Written informed consent was obtained from all participants. A comparison of the intake-only and follow-up samples (including nonstimulant users) showed that a higher proportion of the follow-up sample was married (33% vs. 31.3%, p ⬍ .001), older (Ms ⫽ 33.7 vs. 32.1), and White (40.5% vs. 37.3%), whereas fewer were Hispanic (10.5% vs. 13.3%, p ⬍ .001) and more had a college education (10% vs. 7.9%, p ⬍ .001). A lower proportion of the follow-up sample had experienced depressive symptoms (25.4% vs. 28.5%, p ⬍ .01). There were no significant differences in drug use between the intake-only and follow-up samples.


Measures Data on depression were collected at intake and follow-up, with two measures. The first is derived from a series of self-reported items measuring depressive symptoms in the 12 months before treatment entry. Respondents were classified as having depressive symptoms if they reported at least one 2-week period of feeling sad, blue, or depressed (one question) and having other concurrent problems, such as difficulty sleeping and loss of appetite; having had suicidal thoughts; or having attempted suicide in the previous 12 months.1 The second measure is the Symptom Check List–90 (SCL–90), a self-report depression scale (Derogatis, 1977). Responses are rated on a 5-point scale that ranges from none (0) to extremely (4), representing the degree of discomfort experienced with problems such as having thoughts of ending one’s life, feeling lonely, blue, no interest in things, hopeless about the future, and feelings of worthlessness in the 30 days before treatment. We included both measures to account for depression over the past year and within the past month. Although the entire SCL–90 was not administered at follow-up, the questions measuring depressive symptoms were included. Substance use was measured as the reported number of times per month or per week each drug was used in the year before treatment entry. Drug users were divided into three categories according to their intake reports of drug use. The first group includes individuals who reported at least monthly cocaine use but less than monthly A/MA use (C). The second group includes individuals who reported both cocaine and A/MA use on at least a monthly basis (C⫹A/MA), and the third group includes those who reported at least monthly A/MA use but less than monthly cocaine use (A/MA). Polydrug use was measured as at least monthly use of any of the following drugs in the past 12 months: alcohol, marijuana, cocaine, heroin, other narcotics, hallucinogens, amphetamine, and sedatives. The total number of substances was summed and included as a continuous variable.2 Ever having had a lifetime major depressive episode, measured with questions developed according to Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1987) criteria and incorporated into the baseline interview, was included to control for underlying major depression that may precede substance abuse. Frequency of cocaine use, A/MA use, or both, was included as a control variable with monthly (reference category), weekly, and daily use categories. Heavy alcohol use in the past year, defined as five or more drinks per sitting at least weekly, was included as a control, as alcohol use tends to be associated with depression. Heroin use (at least monthly) in the past year also was included as a control, because some research indicates that this group has lower levels of depression than stimulant users (Craig, 1979). Finally, age at first drug use was included as a lifetime drug use measure.

Results Pretreatment Differences Table 1 provides the demographic breakdown and depressive symptoms by amphetamine and cocaine use category. Because

A/MA use tends to be regionally concentrated, only a small percentage (11.3%) of individuals in this national treatment sample reported using A/MA in the previous year. Sixty-nine percent of the A/MA users combined use with at least monthly cocaine use. Consistent with other samples of A/MA users, those in this study were more likely to be White. Also, the majority of C⫹A/MA users were male, although the A/MA-only users were slightly more likely to be female. At the bivariate level, significantly more C⫹A/MA and A/MA users reported depressive symptoms than users of cocaine only. In addition, the C⫹A/MA group scored significantly higher on the SCL–90 than the cocaine-only group, although post hoc comparisons showed that the average score for the A/MA group was not significantly higher than that for the cocaine-only group. A higher percentage of amphetamine users (both C⫹A/MA and A/MA) had had a major lifetime depressive episode compared with cocaine users. C⫹A/MA users also reported significantly more polydrug use. We conducted a multivariate logistic regression predicting the odds of reporting any depressive symptoms, and a multivariate linear regression predicting SCL–90 depression score, to determine whether differences in depressive symptoms were associated with polydrug use and major lifetime depressive episode. When controlling for these variables, C⫹A/MA users were no more likely to report depressive symptoms, whereas the number of substances used significantly increased the odds of depressive symptoms (see Table 2). Having had a major lifetime depressive episode also increased the odds of having had depressive symptoms in the previous 12 months. The multivariate regression predicting SCL–90 scores (see Table 2, column 3) reveals a similar pattern: When controlling for other characteristics—in particular, polydrug use and major lifetime depressive episode—A/MA use, either in combination with cocaine or alone, was not associated with depressive symptoms.

Posttreatment Differences We examined whether cessation of A/MA use was associated with depressive symptoms. Individuals who reported abstinence from all drugs at the 12-month posttreatment follow-up were selected for this analysis, enabling us to examine whether intake patterns of drug use predicted depression at follow-up. A total of 931 individuals reported abstinence— 838 cocaine users, 59 C⫹A/MA users, and 33 A/MA users. There were no group differences in abstinence rates, but among abstinent individuals the same pattern of depression seen at intake existed at follow-up: More C⫹A/MA users (30.5%) compared with cocaine-only users (17.9%) reported depressive symptoms (analyses not shown). We 1 The depressive symptom item is a self-report measure designed to capture experience of short-term symptoms in the previous year. This measure is correlated .38 with the SCL–90, p ⬍ .001. 2 For the bivariate table, we report total number of substances in addition to stimulant use, because the C⫹A/MA group, by definition, uses at least one more substance than the other two groups. However, for the multivariate analyses, total number of substances, including stimulants, is used, as overall polydrug use is of theoretical interest. Because the relative number of additional substances is the same, the odds ratio for total number of substances would be the same as for number of additional substances.

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Table 1 Sample Characteristics by Drug Use Category


Characteristic Race (%)*** White Black Hispanic Other Age (%)*** 18–24 25–34 35–44 45⫹ Sex (%) Male Female Education (%) ⬍High school High school degree or GED Some college College or advanced Marital status (%) Married/cohabiting Divorced/separated/widowed Never married Depressive symptoms (%)*** SCL–90*** M SD Major lifetime depressive episode (%)*** No. additional substances*** M SD Frequency of use (%) Monthly Weekly Daily

Cocaine (n ⫽ 1,932)

Cocaine ⫹ amphetamine/ methamphetamine (n ⫽ 169)

Amphetamine/ methamphetamine (n ⫽ 75)

31.9 57.6 8.4 2.1

66.9 17.8 12.4 3.0

78.7 10.7 9.3 1.3

9.7 49.1 34.1 7.2

18.3 46.7 30.8 4.1

18.7 54.7 24.0 2.7

65.1 34.9

62.1 37.9

53.3 46.7

32.7 39.5 18.7 9.1

30.2 41.4 16.0 12.4

44.0 40.0 10.7 5.3

32.9 23.9 43.3 25.6

30.8 26.0 43.2 42.0

33.3 28.0 38.7 34.7

1.39 0.97 9.4

1.70 1.01 20.7

1.51 1.01 18.7

2.04 1.15

2.84 1.24

2.03 1.25

24.8 35.2 40.0

17.8 36.1 46.2

30.7 33.3 36.0

Note. SCL–90 ⫽ Symptom Check List–90. *** p ⬍ .001.

then performed a logistic regression to predict depressive symptoms among individuals who remained abstinent, controlling for additional intake variables (analyses not shown). Analyses are available from Kara S. Riehman on request. Although lifetime depressive episode (odds ratio ⫽ 1.91, p ⬍ .01) and depressive symptoms in the year before intake (odds ratio ⫽ 2.87, p ⬎ .001) predicted depressive symptoms at follow-up, none of the intake drug use variables were significant.

Discussion Some studies have reported that A/MA users have higher rates of depression than cocaine users and that these depressive symptoms persist for a longer period of time during recovery. The current study partially supports those findings. Although a bivariate relationship exists between cocaine and amphetamine use and depression, our results indicate that this may be due to the greater likelihood of this group to be polydrug users, or to have had a major lifetime depressive episode, or both. Also, we found no

evidence that depressive symptoms persist after discontinuation of use for a longer period of time among A/MA users than among cocaine users who do not use A/MA. The present findings indicate that the actual properties of A/MA may not contribute to depression, but using multiple substances on a regular basis may. Alternatively, individuals with underlying depression may use multiple substances to self-medicate. Although we were not able to directly test this hypothesis, there is some indication that A/MA users, who are also more likely to be polydrug users, may self-medicate. Benzodiazepine, or sedative, use is associated with psychological and emotional impairment and thus may be an indicator of self-medicating behavior (Darke, Ross, & Cohen, 1994). We found that a greater percentage of A/MA users also reported using sedatives without a prescription (analyses not shown). In addition, other analyses using the DATOS data indicate that a greater number of psychological problems before the onset of weekly drug use is associated with polydrug use before the onset of weekly use (Joshi, Grella, & Hser, 2001). Individuals whose psychological symptoms predate onset

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Table 2 Logistic Regression Predicting Odds of Depressive Symptoms and Multivariate Regression Predicting SCL–90 Scores at Intake Depressive symptoms


Variable Substance use C only C⫹A/MA A/MA only Control variables Lifetime depressive episode No. substances Frequency of use Monthly Weekly Daily Heavy alcohol use past year Used heroin past year Age at first drug use Demographics Sex Male Female Race/ethnicity White Black Hispanic Other Age 18–24 25–34 35–44 45⫹ Education ⬍ High school High school grad Some college College degree⫹ Marital status Married/cohabiting Divorced/separated/widowed Single, never married

Odds ratio

95% CI

SCL–90

␤ ref. ⫺0.042 ⫺0.076

SE

ref. 1.271 1.087

0.87–1.87 0.64–1.85

4.452*** 1.154**

3.32–5.97 1.03–1.29

0.807*** 0.086***

0.065 0.022

ref. 1.158 1.319* 1.063 0.627*** 0.992

0.88–1.52 1.01–1.73 0.86–1.32 0.48–0.83 0.97–1.02

ref. 0.113 0.276*** 0.193*** ⫺0.232*** ⫺0.007

0.053 0.052 0.043 0.053 0.005

ref. 1.089

0.88–1.35

ref. 0.301***

0.043

ref. 0.856 1.193 0.889

0.67–1.09 0.83–1.73 0.45–1.76

ref. ⫺0.128** ⫺0.158* ⫺0.256

0.048 0.075 0.139

ref. 0.778 0.646* 0.566*

0.56–1.08 0.45–0.94 0.32–0.99

ref. 0.135* 0.098 0.037

0.068 0.076 0.109

ref. 1.016 1.129 1.163

0.80–1.29 0.84–1.51 0.80–1.70

ref. ⫺0.017 0.073 0.062

0.047 0.058 0.075

ref. 1.173 0.879

0.90–1.53 0.69–1.12

ref. ⫺0.021 0.045

0.053 0.047

0.082 0.110

Note. N ⫽ 2,176. SCL–90 ⫽ Symptom Check List–90; CI ⫽ confidence interval; C ⫽ cocaine; ref. ⫽ reference group; A/MA ⫽ amphetamine/methamphetamine. * p ⬍ .05. ** p ⬍ .01. *** p ⬍ .001.

of weekly drug use are more likely to have experimented with many drugs before initiating weekly use. This provides support for the notion that polydrug users tend to exhibit this behavior as a result of underlying psychological problems or depression. The DATOS data set does not contain information on age of depression onset; therefore, temporal sequencing of depression and drug use is not possible. However, our findings support the view that higher rates of depression among A/MA users is due to underlying depression or psychological problems rather than that A/MA use causes depression. Several limitations should be noted. Data for this study were collected in the early 1990s, before the dramatic increase in A/MA use seen in the mid- to late 1990s. Increasing prevalence may have resulted in a more diverse group of A/MA users with different characteristics than those in this study, further limiting generalizability. However, more recent studies of A/MA users show that

polydrug use and psychiatric symptoms are still common and that gender, age, and education levels of DATOS A/MA and cocaine users in treatment are very similar to those in more recent treatment studies (Huber et al., 1997; Rawson et al., 2002). These findings indicate some similarity among past and more recent users. The DATOS sample does not represent A/MA users in the heart of the epidemic on the West coast; however, findings from more recent studies in these cities are consistent with those in the present study. For instance, many methamphetamine users in Los Angeles are gay and bisexual males, and ethnographic research indicates that these users self-medicate with methamphetamine to deal with emotional and physical pain associated with their sense of hopelessness and isolation (Reback, 1997). Although our findings are consistent with this, data from a nationally representative sample may obscure such important regional, situational, or contextual factors.

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Received May 8, 2001 Revision received December 10, 2001 Accepted December 13, 2001 䡲